WHITE MUSCLE STILL ON SCENE

Press, 17 September 1976, Page 14

WHITE MUSCLE STILL ON SCENE

Mr R. C. Gumbrell, veterinary investigation officer at the Animal Health Laboratory of the Ministry of Agriculture and Fisheries at Lincoln, is the writer of the accompanying item on white muscle disease in lambs and calves. It seems almost an age ago now since white muscle was a widespread problem in lambs and then selenium was found to be a spectacular breakthrough in its treatment and in countering other problems with sheep grazing improved pastures.

Trace element deficiencies vary from season to season and with the type of farming. This is reflected in the continuing occurrence of white muscle disease in lambs in some instances, in spite of the use of selenium.

Calves are also proving just as susceptible to white muscle disease as lambs, as calf raising becomes more common on improved pastures. Selenium deficiency can be manifested in several different ways in sheep. In lambs and hoggets it can cause white muscle disease, a degeneration of the muscles. If it affects the heart, death is usually sudden — this is more common in lambs up to four weeks old. If the leg muscles are affected, the animal shows a type of paralysis. 111-thrift and poor wool production in sheep can be caused by selenium deficiency and seleniumdeficient ewes may be infertile.

recommended by their veterinarian possibly years ago. But recent experience has shown that some of these standard procedures are insufficient to prevent white muscle disease in lambs. Problems of sudden death or poor growth in lambs between birth and weaning should be investigated by the farmer’s veterinarian. He will check for white muscle disease and other diseases, and will give advice appropriate to the problem. Changes in the lambs’ selenium requirements are probably reflections of changing pasture species and growth rates. Calves are also susceptible to white muscle disease before weaning. In the spring of 1975 several outbreaks of the condition occurred in the Ashburton county. Most

Many farmers have a standard procedure for prevention of these conditions

were on properties where selenium was used with sheep, but not with cattle, which was a relatively new type of farming for this area.

The best calves In the herd died suddenly. Their heart muscle was damaged by white muscle disease, and the weakened heart was suddenly not able to cope with the strain of a rapidly growing animal. Prompt veterinary investigation and treatment of the problem prevented large losses.

Selenium is a poison as well as a trace element. In some parts of the world there are plants which concentrate selenium and cause selenium poisoning in grazing stock.

Outbreaks of selenium poisoning in sheep, cattle and pigs occur every year in New Zealand, when the substance is used carelessly and not as prescribed by a veterinarian. Although it is not a cumulative poison (i.e. it is not stored in the body), its use is under veterinary control to prevent stock losses and

high selenium levels in animal products. Selenium has been called a wonder element. It is not. But deficiencies of selenium can be readily diagnosed and successfully treated by a veterinarian, relegating it to the status of another problem of farming that is able to be solved.